coin size battery used for in arcade games

[vanwatson]

What is the coin size battery used for in arcade games? it's for the settings and to keep
the EPROM chips turned on when the power is off.

The Battery goes to the watch dog circuit?

The battery sometimes stores the high score or settings

When I remove the Battery from the Logic board, the logic board doesn't work, why?

Some Arcade logic boards don't have the battery but other Arcade logic boards do use a Coin size battery

[ed12]

any logic board that has nvram will have a battery of some type
button batt/tripple a's/and or a dallas chip which has the bat built in to it

the bat is used to keep the nvram up and alive
to save time/date/and in our case game information.
but i have never seen a board not fire up with out 1,the board would just default
to it's bios setting's from the eprom

ed

[vanwatson]

the bat is used to keep the nvram up and alive

NonVolatile Ram NVRAM
I know now of days they use NVRAM adapters

what do they mostly use the NVRAM for? just to keep the high score? and the bookkeeping?

I have seen those Dallas chips , Nonvolatile sram DS1220AD-200 , any reason why they used those Dallas chips?

The advantage of using the Dallas chips was to not get the battery leaking and alkaline corrosive on the PCB board

[ed12]

correct on both statements
and the adapter was is used when a mfg stops making nvram that they built using there own die's,and never sold the die's

ed

[vanwatson]

The battery section is mostly at 3 VDC , but some logic boards need it higher then 3 volts depending on the NVRAM chip?

Sometimes you have to use a higher voltage coin cell battery for the NVRAM chip to work for some reason

When Logic boards don't use a NVRAM chip, where do they store the settings at? coin settings, game settings, etc.

The Arcade game Robotron NVRAM chip stored the coin settings , game settings etc. when there is no battery it won't store anything

But most games don't use the NVRAM chips to store coin settings and the games settings, so where do they store it at?

[ed12]

no all game's use fourm of nvram
newer multi game's 39in1/69in1 are olny a hand full i can talk to that do not have a battery back up...but then u can always use static ram..??, i would need to look at my spare 39in1 to see where it would be stored..
but that aside 90% of game's make use of a battery back-up of some type..
and a good button batt 2032 is good for 3.6volts
3-x-1.5=?
2-x-1.5=?
1=4.5 volt's
1=3 volt's
upper lower range for nvram
most use 3volt >cheaper<
in a pinball it is alway's 3-x-1.5=4.5
in a video game button batt 3-3.6volt's
dallas chip's that read out 3volt are on there down side
as they come out 3.6volt's

ed

[vanwatson]

dallas chip's that read out 3volt are on there down side
as they come out 3.6volt's

So when a Dallas chip or NVRAM chip is going older in age, faulty or bad , it will measure 3 volts instead of 3.6 VDC?

The Coin size battery 3 volts, have less current? then using 3X 1.5 batterys have more current output then using 1 coin size battery?
The Dallas chips and NVRAM chips need about 1 amp of current

When you undervoltage a NVRAM chip like at 3 volts which is at it's min range, does this cause problems?

[ed12]

the example of 3 is for refernce
but yes they start to go corupt..ie goffie high score's/time/date etc

and no they do not draw 1amp
it is mili amp's,rember they are olny used when the power to the device is off
so very very low current is needed as the bat olny power's 1 chip
and olny a few cell's of the chip are kept active >mem< cell's

ed

[vanwatson]

but yes they start to go corupt..ie goffie high score's/time/date etc

Yes true

Thanks for the help

[vanwatson]

The Journey Arcade game will not boot up or start with no battery . I needs the batteries 5 volts to start the watchdog circuit, reset circuit, boot up

The watchdog has some kind of voltage sensing , maybe take a look at the schematic of Journey Arcade game in the early 80's to know why it needs the battery to boot up

[ed12]

the easy reason is the wdt is tied to the batt

some early bally pin's used this same design flaw

ed

[vanwatson]

the watch dog circuit is tied to the battery?

What is the Vbat?

The watch dog circuit just resets the CPU when the CPU locks up, what else does the watch dog circuit do?